Rotary kiln precooler construction

ABSTRACT

A precooler for a rotary kiln comprises a hollow body having a flared inlet for connection to the discharge end of a rotary kiln, a cylindrical central portion of greater diameter than that of the kiln, and a tapered outlet having circumferentially spaced cooling tubes arranged on a circle having a diameter less than that of the central portion. The central portion preferably includes a liner having grooves extending between the inlet and the outlet.

Sehiissler et al.

ROTARY KILN PRECOOLER CONSTRUCTION [75] Inventors: Werner Schiissler, 473 Ahlen;

Otto Heinemann, 4722 Ennigerloh, both of Germany [73] Assignee: Polysius AG, Graf-Galen-Strasse,

Germany [22] Filed: Feb. 3, 1972 [21] Appl. No.: 223,150

[30] Foreign Application Priority Data Feb. 25, 1971 Germany P 21 09 065.3

[52] US. Cl 432/80, 432/26, 432/115, 34/134, 34/135 [51] Int. .Cl. F27b 7/38 [58] Field of Search 263/32; 34/134, 135; 432/26, 115, 80

[56] References Cited UNITED STATES PATENTS 3,358,977 l2/l967 Jensen 432/80 2,845,259 7/1958 Henrichscn 432/80 Aug.7, 1973 1,008,974 11/1911 Lindhard 263/32 R 1,675,416 7/1928 Lindhard... 263/32 R 3,547,418 12/1970 Jensen t 263/32 R 3,502,139 3/1970 Andersen 263/32 C FOREIGN PATENTS OR APPLICATIONS 1,332,702 6/1963 France 263/32 R Primary Examiner.1ohn J. Camby Assistant ExaminerI-Ienry C. Yuen Attorney-John F. Learman et al.

[57] ABSTRACT 11 Claims, 2 Drawing Figures ROTARY KILN PRECOOLER CONSTRUCTION This invention relates to a rotary kiln with a precooler connected to its outlet, the precooler having a diameter greater than that of the rotary kiln and being connected to cooling tubes disposed in satellite manner relative to the kiln axis.

A rotary kiln of the general type to which the invention relates is known and in which cooling tubes disposed in satellite manner are connected by their inlet stubs to the peripheral area of the precooler which has the maximum diameter. In that construction the axes of the precooler outlets are generally perpendicular to the axis of the rotary kiln. In such construction, the hot material discharged from the rotary kiln outlet is intended to be precooled before its entry into the cooling tubes. lf cement clinker, for instance, is processed in a rotary kiln, very coarse material usually emerges from the kiln outlet. Due to the design of the known precooler, both the precooler outlets and the cooling tube inlet stubs are subjected to considerable impact and temperature stresses, which results in rapid wear and hence frequent replacement of these parts and also of the linings in these regions. Also, since the emerging coarse clinker is generally of very irregular shape, there are frequently troublesome stoppages caused by the larger lumps during their transit from the precooler to the cooling tubes.

The object of the invention is therefore to provide a rotary kiln of the type described which, as compared with known constructions, ensures considerably improved precooling of the fired material, together with reduced susceptibility to wear and stoppages in the above-mentioned parts.

According to the invention this object is achieved in that the cooling tubes are connected to the end face of the precooler remote from the rotary kiln outlet, and the section of the precooler lying between the rotary kiln outlet and the cooling tubes has a grooved lining.

Because of the construction of the precooler and its adjacent cooling tubes in accordance with the invention, the fired material must first pass the grooved lining of the precooler before it can enter the cooling tubes connected to the end face. Because of the considerably increased internal surface of the precooler as compared with known constructions, the material is more strongly cooled as it passes the grooved lining. In addition at least those lumps of material which are less strongly burned together are largely broken down, so that these pieces can no longer lead to stoppages inthe region of the cooling tube inlets. Since in accordance with the invention the cooling tubes are connected to the end face remote from the rotary kiln outlet, there is a relatively careful transition from the precooler into the cooling tubes, whereby the impact effect of the coarser pieces of material, which in the known designs led to rapid wear and to damage, is largely prevented.

An advantageous embodiment of the invention is achieved if in its region of maximum diameter the precooler has a cylindrical part which is connected to the rotary kiln outlet by a conical part which flares or tapers against the feed direction of the material, and whose inner side in general supports the grooved lining. In this way in particular the grooved lining can be provided in the precooler in relatively simple manner. In order that the material which mainly slides along the internal periphery of the precooler can emerge at reduced speed from the precooler, the centre axes of the material outlet apertures of the precooler leading to the cooling tubes lie on an imaginary circle whose diameter is less than that of the cylindrical part of the precooler.

The grooved lining is formed either with straight grooves running generally parallel to the longitudinal axis of the rotary kiln or with generally helical grooves, these grooves in either case being directed towards the individual material outlets in the precooler. In this way the time the material spends in the precooler can be matched to the output of the rotary kiln.-

Finally, it is desirable for the cooling tubes to lie parallel to the rotary kiln axis, and to be supported on a carrier pipe which is connected to the end face of the precooler joined to the cooling tubes, and is generally coaxial with the kiln and with the cylindrical part of the precooler. This provides a particularly robust construction of the rotary kiln in accordance with the invention.

One embodiment of the invention is described below with reference to the drawings. In these:

FIG. 1 is a partial view, partly cut away, of a rotary kiln precooler constructed in accordance with the invention; and

FIG. 2 is a cross-section through the precooler on the line IIII of FIG. 1. I

FIG. 1 only shows the outlet 1 of the actual rotary kiln. This rotary kiln outlet 1 is connected to the precooler 2 provided by the inventionQand has an outlet 3 remote from the rotary kiln outlet to which are connected cooling tubes 4 (only two shown) which are dis.- posed in satellite manner about theaxis 5 of the rotary kiln.

The precooler 2 consists in general of a conical, flared inlet part 6, a cylindrical part7 and the tapered outlet 3 already referred to. The conical'part 6 tapers against the direction offeed of material (arrow 8) and its edge with the smallest diameter is connected to the rotary kiln outlet 1. At the opposite end of the cone (with the largest diameter) there is attached the cylindrical part 7 of the precooler, which thus has a considerably larger diameter than the rotary kiln. As has been demonstrated by test, it is desirable for the axial length L of this cylindrical part 7 to be no greater, and preferably less, than the diameter D of the rotary kiln. The inside of the cylindrical part 7 carries a grooved lining 9, having straight grooves 10 lying generally parallel to the longitudinal axis 5 of the rotary kiln (see also FIG. 2). Each groove is disposed so that it is directed toward an outlet aperture 11 for material from the precooler 2.

If relatively intense precooling is to be provided by the precooler 2, it may be desirable for the grooves in the grooved liningto be generally helical (see dotted line groove 10 in FIG. I).

With the embodiment shown in the drawings, the outlet 3 of the cooler 2 remote from the rotary kiln outlet 1 consists of a number of conical parts 3', 3" and an aperture 12 coaxial with the longitudinal axis 5 of the rotary kiln. The conical part 3 directly attached to the cylindrical part includes the material outlet apertures I], referred to above, of the precooler 2. The centre axes of the material outlet apertures l 1 lie on an imaginary circle whose diameter D, is smaller than the diameter D of the cylindrical part 7 of the cooler. By

this means the hot material emerging from the rotary kiln outlet 1 cannot drop down directly out of the'precooler 2. The feed rate and thus the kinetic energy of the material are first somewhat reduced by.this arrangement, in accordance with the invention, of the outlets 11, so that the coarser pieces of material in particular cannot cause any damage through excessive impact effect on their passage from the precooler 2 into the cooling tubes 4.

The cooling tubes 4 are parallel to the rotary kiln axis 5 and extend in a direction opposite to the kiln outlet 1. The longitudinal axes 4 of the cooling tubes 4 also lie on an imaginary circle, whose diameter D is however larger than the diameter D of the circle on which lie the material outlets 1 l. The cooling tubes 4 are connected to the end wall 3 or to the conical part 3' thereof by stubs 13 which are inclined relative to the longitudinal axes 4' of the cooling tubes. Each cooling tube 4 or its stub 13 is connected to a precooler outlet aperture 1 l.

The conical part 3" of the outlet 3 is connected to a carrier pipe 14, substantially coaxial with the kiln and with the cylindrical part 7 of the precooler. The cooling tubes 4 are supported on this carrier pipe 14 by suitable supports 17. This carrier pipe 14 can be provided at its free end with a support ring (not shown) mounted on rollers or the like.

Generally concentrically in. the carrier pipe is mounted a burner 15 (indicated only), which passes through the precooler 2 into the rotary kiln itself. The burner 15 thus passes through the aperture 12 in the end wall 3', which otherwise is preferably closed by a cover 16.

It will be understood that further embodiments of the rotary kiln and cooler are possible within the scope of the invention. Thus, the outlet end wall of cooler 2 can, if desired, comprise a generally straight, non-tapered wall. In addition, the precooler 2 can have observation holes and means which will permit an operative to break up any large lumps of material which may be difficult to reduce in size.

What is claimed is:

l. A precooler adapted for use with a rotary kiln comprising a hollow body rotatable about a substantially horizontal axis, said body having a cylindrical portion; a flared inlet in communication with one end 4 of said cylindrical portion; and 'a plurality of spaced outlet openings in communication with the'other end of said cylindrical portion, said outlet openings being spaced circumferentially about a circle having a diameter less than that of said cylindrical portion.

2. The construction set forth in claim 1 wherein said inlet flares in the direction of said cylindrical portion.

3. The construction set forth in claim 1 wherein said cylindrical portion supports a liner having spaced grooves therein.

4. The construction set forth in claim 3 wherein said grooves extend substantially axially of said body.

5. The construction set forth in claim 3 wherein said grooves extend substantially helically of said body.

6. The construction set forth in claim I wherein said cylindrical portion of said body has an axial length no greater than the diameter of the rotary kiln with which said precooler is adapted for use.

7. The construction set forth in claim 1 including discharge tubes arranged on a circle having a diameter greater than that of said cylindrical part, and means connecting said tubes to said outlet openings.

8. The construction set forth in claim 7 wherein said connecting means comprise radially outwardly inclined stubs interposed between said body and said tubes.

9. The construction set forth in claim 1 wherein said body includes a tapered wall downstream from said cylindrical portion and in which said outlet openings are formed.

10. The construction set forth in claim 7 wherein said tubes are substantially parallel to the axis of rotation of said body.

11'. A precooler adapted for use with a rotary kiln comprising a rotatable, hollow body having a cylindrical portion; an inlet in communication with one end of said cylindrical portion; outlet tubes in communication with the opposite end of said cylindrical portion and spaced circumferentially about the axis of rotation of said body; and a grooved lining carried by said cylindrical portion on the inner surface thereof. 

1. A precooler adapted for use with a rotary kiln comprising a hollow body rotatable about a substantially horizontal axis, said body having a cylindrical portion; a flared inlet in communication with one end of said cylindrical portion; and a plurality of spaced outlet openings in communication with the other end of said cylindrical portion, said outlet openings being spaced circumferentially about a circle having a diameter less than that of said cylindrical portion.
 2. The construction set forth in claim 1 wherein said inlet flares in the direction of said cylindrical portion.
 3. The construction set forth in claim 1 wherein said cylindrical portion supports a liner having spaced grooves therein.
 4. The construction set forth in claim 3 wherein said grooves extend substantially axially of said body.
 5. The construction set forth in claim 3 wherein said grooves extend substantially helically of said body.
 6. The construction set forth in claim 1 wherein said cylindrical portion of said body has an axial length no greater than the diameter of the rotary kiln with which said precooler is adapted for use.
 7. The construction set forth in claim 1 including discharge tubes arranged on a circle having a diameter greater than that of said cylindrical part, and means connecting said tubes to said outlet openings.
 8. The construction set forth in claim 7 wherein said connecting means comprise radially outwardly inclined stubs interposed between said body and said tubes.
 9. The construction set forth in claim 1 wherein said body includes a tapered wall downstream from said cylindrical portion and in which said outlet openings are formed.
 10. The construction set forth in claim 7 wherein said tubes are substantially parallel to the axis of rotation of said body.
 11. A precooler adapted for use with a rotary kiln cOmprising a rotatable, hollow body having a cylindrical portion; an inlet in communication with one end of said cylindrical portion; outlet tubes in communication with the opposite end of said cylindrical portion and spaced circumferentially about the axis of rotation of said body; and a grooved lining carried by said cylindrical portion on the inner surface thereof. 